Back to EveryPatent.com
| United States Patent |
6,235,026
|
|
Smith
|
May 22, 2001
|
Polypectomy snare instrument
Abstract
A surgical snare instrument according to several embodiments includes a
first handle capable of controlling the rotational position of the snare,
and a second handle adapted to control the opening and closing of the
snare and cauterization. The first handle serves as a grippable element on
the sheath and contains a system which rotates the shaft, and consequently
the snare, so that when the physician grips the first handle, the
physician is capable of steering the snare by operating the first handle.
In addition, the physician is also capable of positioning the entire
sheath relative to the endoscope by sliding the sheath into and out of the
working channel of the endoscope. The proximal handle is operable by an
assistant and permits longitudinal movement of the shaft and cautery
application. According to other embodiments, the snare instrument is
provided with a mount which enables the snare instrument to be adjustably
fixed relative to an endoscope handle. Additionally, an embodiment is also
provided in which a single handle provides a physician with a system which
advances and retracts the sheath of the snare instrument relative to the
endoscope, a system which opens and closes the snare, and a system which
rotates the shaft and the snare to position the snare over a polyp.
| Inventors:
|
Smith; Kevin W. (Coral Gables, FL)
|
| Assignee:
|
SciMed Life Systems, Inc. (Maple Grove, MN)
|
| Appl. No.:
|
369724 |
| Filed:
|
August 6, 1999 |
| Current U.S. Class: |
606/46; 606/47; 606/113 |
| Intern'l Class: |
A61B 018/18 |
| Field of Search: |
606/41,45-52,110-113
|
References Cited
U.S. Patent Documents
| D301614 | Jun., 1989 | Kozak et al.
| |
| 1127948 | Feb., 1915 | Wappler.
| |
| 3895636 | Jul., 1975 | Schmidt.
| |
| 3955578 | May., 1976 | Chamness et al.
| |
| 4256113 | Mar., 1981 | Chamness | 606/47.
|
| 4294254 | Oct., 1981 | Chamness.
| |
| 4326530 | Apr., 1982 | Fleury, Jr.
| |
| 4345599 | Aug., 1982 | McCarrell.
| |
| 4590938 | May., 1986 | Segura et al.
| |
| 4619260 | Oct., 1986 | Magill et al.
| |
| 4763636 | Aug., 1988 | Macek et al.
| |
| 4785825 | Nov., 1988 | Romaniuk et al.
| |
| 4840176 | Jun., 1989 | Ohno.
| |
| 4872456 | Oct., 1989 | Hasson.
| |
| 4905691 | Mar., 1990 | Rydell.
| |
| 4945920 | Aug., 1990 | Clossick.
| |
| 5026371 | Jun., 1991 | Rydell et al.
| |
| 5066295 | Nov., 1991 | Kozak et al.
| |
| 5084054 | Jan., 1992 | Bencini et al.
| |
| 5147373 | Sep., 1992 | Ferzli.
| |
| 5163942 | Nov., 1992 | Rydell.
| |
| 5176702 | Jan., 1993 | Bales et al.
| |
| 5201743 | Apr., 1993 | Haber et al.
| |
| 5254117 | Oct., 1993 | Rigby et al. | 606/46.
|
| 5254130 | Oct., 1993 | Poncet et al.
| |
| 5281220 | Jan., 1994 | Blake, III | 606/46.
|
| 5281230 | Jan., 1994 | Heidmueller.
| |
| 5290294 | Mar., 1994 | Cox et al. | 606/108.
|
| 5439478 | Aug., 1995 | Palmer.
| |
| 5501692 | Mar., 1996 | Riza.
| |
| 5542948 | Aug., 1996 | Weaver et al.
| |
| 5601533 | Feb., 1997 | Hancke et al.
| |
| 5741271 | Apr., 1998 | Nakao et al.
| |
| 5746747 | May., 1998 | McKeating.
| |
| 5755724 | May., 1998 | Yoon | 606/114.
|
| 5759187 | Jun., 1998 | Nakao et al. | 606/114.
|
| 5800444 | Sep., 1998 | Ridinger et al.
| |
| 5814052 | Sep., 1998 | Nakao et al.
| |
| 5820464 | Oct., 1998 | Parlato.
| |
| 5846248 | Dec., 1998 | Chu et al.
| |
| 5860975 | Jan., 1999 | Goble et al.
| |
| 5906621 | May., 1999 | Secrest.
| |
| 5957932 | Sep., 1999 | Bates et al.
| |
| 5984920 | Nov., 1999 | Steinbach.
| |
| 6001096 | Dec., 1999 | Bissinger et al. | 606/50.
|
| 6024708 | Feb., 2000 | Bales et al.
| |
| Foreign Patent Documents |
| WO 00/42926 | Jul., 2000 | WO.
| |
| WO 00/53107 | Sep., 2000 | WO.
| |
Other References
Product Brochure, "Trio 14, Re-engineering Over-the-Wire Balloon
Technology," 1994, 4 pages.
|
Primary Examiner: Peffley; Michael
Attorney, Agent or Firm: Crompton, Seager & Tufte, LLC
Claims
What is claimed is:
1. A surgical instrument for insertion through an endoscope having a handle
and a working channel, said surgical instrument comprising:
a) an elongate flexible tubular sheath having a proximal and distal ends;
b) a flexible shaft extending through and axially movable relative to the
sheath, said sheath having proximal and distal ends;
c) an end effector coupled to or formed at said distal end of said shaft;
d) a first means coupled to said shaft for rotating said shaft relative to
said sheath wherein said first means is a first handle including a first
member and including a second member provided with a bore, said second
member being axially rotatable relative to said first member, said first
member having a distal end fixedly coupled to said proximal end of said
sheath and a proximal end coupled to said distal end of said tubular
member, said shaft extending through said bore, and said second member
having means for engaging said shaft such that rotation of said second
member relative to first member causes rotation of said shaft relative to
said sheath;
e) a second means for longitudinally moving said shaft relative to said
tubular sheath; and
f) a tubular member coupling said first and second means together.
2. A Surgical instrument according to claim 1, wherein:
said end effector is a snare.
3. A surgical instrument according to claim 1, wherein:
said tubular member is flexible.
4. A surgical instrument according to claim 1, wherein:
said first means is located distal said second means.
5. A surgical instrument according to claim 1, wherein:
said shaft includes a key portion provided with a non-circular cross
section, and said means for engaging said shaft is a non-circular cross
section of said bore of said second member adapted to engage said key
portion.
6. A surgical instrument according to claim 5, wherein:
said second member is provided with a tubular portion which extends at
least partially into said proximal and distal ends of said first member,
said tubular portion having said bore with said non-circular cross
section.
7. A surgical instrument according to claim 6, wherein:
said tubular portion of said second member extends beyond said proximal and
distal ends of said first member.
8. A surgical instrument according to claim 1,
wherein said second means for longitudinally moving said shaft relative to
said sheath includes a first member having a throughbore and a distal end
coupled to said proximal end of said tubular member, and a second member
coupled to said shaft and movable relative to said first member to cause
said shaft to move longitudinally relative to said sheath.
9. A surgical instrument according to claim 8, wherein:
said second member is longitudinally slidable relative to said first
member.
10. A surgical instrument according to claim 1, wherein:
said shaft comprises a first element extending from said end effector to a
location proximal said first means, and a second element extending from
said location to said second member of said second means, said first and
second elements being freely axially rotatable relative to each other.
11. A surgical instrument according to claim 10, wherein:
said first and second elements are coupled by a swivel joint.
12. A surgical instrument according to claim 10, wherein
said first element of said shaft is camber-free.
13. A surgical instrument according to claim 1, wherein:
said shaft is freely axially rotatable relative to said second means.
14. A surgical instrument according to claim 13, wherein:
said shaft is camber-free.
15. A surgical instrument according to claim 1, further comprising:
g) a first stiffening sleeve, wherein said sheath is coupled to said first
means and said stiffening sleeve is provided over a portion of said sheath
at or adjacent a coupling of said sheath to said first means.
16. A surgical instrument according to claim 15, further comprising:
h) a second stiffening sleeve provided over a portion of said tubular
member at or adjacent a coupling of said tubular member to said first
means.
17. A surgical instrument according to claim 1, further comprising:
g) means for providing a cautery current to said shaft.
18. A surgical instrument according to claim 1, further comprising:
g) mounting means for mounting said first means relative to the handle of
the endoscope such that said sheath of said surgical instrument extends
through the working channel of the endoscope.
19. A surgical instrument according to claim 17, wherein:
said mounting means is adapted to adjustably fix said distal end of said
sheath relative to a distal end of the endoscope.
20. A surgical instrument for insertion through an endoscope having a
handle and a working channel, said surgical instrument comprising:
a) a elongate flexible tubular sheath having proximal and distal ends;
b) a flexible shaft extending through and axially movable relative to the
sheath, said shaft having proximal and distal ends;
c) an end effector coupled to or formed at said distal end of said shaft,
said end effector capable of being positioned in open and closed
positions; and
d) a handle including coupling means for coupling said handle to the
endoscope handle, and further including,
i) first means for longitudinally moving said sheath relative said working
channel of the endoscope,
ii) second means for longitudinally moving said shaft relative to said
sheath such that said end effector is movable between open and closed
positions determined by relative positions of said sheath and said shaft,
and
iii) third means for axially rotating said shaft relative to said sheath.
21. A surgical instrument according to claim 20, wherein:
said end effector is a snare.
22. A surgical instrument according to claim 20, wherein:
said shaft is freely axially rotatable relative to said second means.
23. A surgical instrument according to claim 20, wherein:
said shaft includes a key portion provided with a non-circular cross
section, and said third means includes means for engaging said key
portion.
24. A surgical instrument according to claim 20, wherein:
said third means i s located distal said second means, and said shaft
comprises a first element extending from said end effector to a location
proximal said third means, and a second element extending from said
location to said second means, said first and second elements being freely
axially rotatable relative to each other.
25. A-surgical instrument according to claim 24, wherein:
said first and second elements are coupled by a swivel joint.
26. A surgical instrument according to claim 24, wherein
said first element of said shaft is camber-free.
27. A surgical instrument according to claim 20, wherein:
said shaft is freely axially rotatable relative to said third means.
28. A surgical instrument according to claim 27, wherein:
said shaft is camber-free.
29. A surgical instrument according to claim 20, further comprising:
e) means for providing a cautery current to said shaft.
30. A surgical instrument for insertion through an endoscope having a
handle and a working channel, said surgical instrument comprising:
a) a elongate flexible tubular sheath having proximal and distal ends;
b) a flexible shaft extending through and axially movable relative to the
sheath, said shaft having proximal and distal ends;
c) an end effector coupled to or formed at said distal end of said shaft;
d) a first means for rotating said shaft relative to said sheath;
e) a second means for longitudinally moving said shaft relative to said
sheath; and
f) a means for fixedly coupling said surgical instrument relative to the
handle of the endoscope, said means for fixedly coupling includes a first
portion couplable to the endoscope and a second portion coupled to said
sheath and longitudinally adjustably fixable relative to said first
portion, such that said sheath may be longitudinally adjusted relative to
the working channel.
31. A surgical instrument according to claim 30, wherein:
said end effector is a snare.
32. A surgical instrument according to claim 30, wherein:
said shaft is freely axially rotatable relative to said second means.
33. A surgical instrument according to claim 30, wherein:
said shaft includes a key portion provided with a non-circular cross
section, and said first means includes means for engaging said key
portion.
34. A surgical instrument according to claim 30, wherein:
said first means is located distal said second means, and said shaft
comprises a first element extending from said end effector to a location
proximal said first means, and a second element extending from said
location to said second means, said first and second elements being freely
axially rotatable relative to each other.
35. A surgical instrument according to claim 34, wherein:
said first and second elements are coupled by a swivel joint.
36. A surgical instrument according to claim 34, wherein
said first element of said shaft is camber-free.
37. A surgical instrument according to claim 30, wherein:
said shaft is freely axially rotatable relative to said second means.
38. A surgical instrument according to claim 37, wherein:
said shaft is camber-free.
39. A surgical instrument according to claim 30, further comprising:
e) means for providing a cautery current to said shaft.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to surgical instruments. More particularly,
this invention relates to a surgical snare instrument for excising polyps.
2. State of the Art
Polypectomy snare instruments are used for the endoscopic removal of
hypertrophic tissue growths within a body cavity, and particularly within
the colon. Polypectomy snare instruments generally include an elongate
tubular member, such as a catheter sheath, a shaft extending through the
tubular member, an elastic wire forming a snare (loop) at the distal end
of the shaft, and a handle for moving the shaft distally and proximally
within the tubular member. The snare can be opened by moving the snare
beyond the distal end of the sheath and closed by retraction of the snare
into the tubular member, each effected by movement of the shift relative
to the sheath.
In operation, a physician introduces the distal end of the instrument, with
the snare of the snare instrument in a retracted position, through the
working channel of an endoscope until the sheath begins to extend out of
the distal end of the endoscope. The physician then directs an assistant,
who has control of the handle of the snare instrument, to open the snare.
The assistant accomplishes this function by moving two portions of the
handle relative to each other. The physician then advances and retracts
the sheath into and out of the endoscope, while applying torque to some
portion of the instrument to position the snare loop over and around a
polyp. Once the snare loop is positioned around the polyp, the physician
orders the assistant to close the snare around the polyp. Then, the
physician or assistant energizes a source of electrocautery current
coupled to the shaft to desiccate, sever, and cauterize the polyp.
Finally, the polyp is removed by withdrawing the snare (or, in some cases,
the polyp is retrieved by use of another instrument such as a biopsy
forceps). In a variation of the procedure, the physician uses suction
applied to a channel of the endoscope to remove the polyp or to hold it to
the end of the endoscope.
Prior art snare instruments have several problems. First, it is difficult
for the physician to precisely position the snare because the physician
relies on gripping the small, slippery sheath over the shaft near where
the sheath enters the endoscope handle. Typically, it is necessary for the
physician to repeatedly push, pull, and torque the sheath and the shaft of
the instrument in order to achieve the desired position with the snare
around the polyp. Second, the prior art instruments are not capable of
efficient steering, because the shaft which is generally used is a cable
having low torsional stiffness, and is not usually free of camber or
"set". The result of these defects is that when the instrument is used in
a tightly-flexed endoscope, the distal end of the snare does not respond
directly to torsional input on the shaft where it enters the endoscope
handle; i.e., rather than directly respond to torsional input from the
physician, the shaft stores the torsional force and upon reaching a
threshold, uncontrollable rotationally whips to release the force. Third,
while several attempts have been made at providing a snare instrument with
a handle adapted to more adeptly steer the snare, most of such prior art
instruments do not specifically allow for rotating the snare to position
it relative to the polyp. Rather, the physician must rotate the shaft of
the instrument by tightly gripping and rotating the sheath where it enters
the endoscope to try to maneuver the snare over the polyp. In addition, in
the several prior art devices specifically adapted for rotational control,
e.g., U.S. Pat. No. 5,066,295 to Kozak et al. and U.S. Pat. Nos.
3,955,587, 4,256,113, and 4,294,254 to Chamness et al., the rotational
control function is placed in the handle at the proximal end of the
instrument. This handle then controls the extension and retraction of the
snare loop as well as the rotation of the snare loop. However, this handle
is typically held by the assistant, so the physician must orally direct
the assistant to coordinate the handle controls while the physician moves
the jacket in and out of the endoscope. As a result, these instruments
have not been widely accepted by physicians.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a snare instrument
which permits the physician to control all aspects of positioning the
snare loop relative to the polyp, while allowing the assistant to perform
the cauterizing and severing of the polyp.
It is a further object of the invention to provide a snare instrument which
provides to the physician the means for advancing and retracting the
distal end of the snare instrument through the endoscope, as well as
rotating the snare, and which provides to the assistant the means for
extending and retracting the snare loop from the sheath of the snare
instrument.
It is another object of the invention to provide a snare instrument in
which the physician has direct and immediate control of the entire
instrument.
It is also an object of the invention to provide a snare instrument which
obviates the need for an assistant during a polypectomy procedure.
It is yet another object of the invention to provide a snare instrument
which improves the speed and efficiency of a polypectomy procedure.
In accord with these objects, which will be discussed in detail below, a
surgical snare instrument is provided. The snare instrument includes an
elongate flexible tubular sheath, a flexible shaft extending through and
axially movable relative to the sheath, a snare coupled to or formed at
the distal end of the shaft, and a system to move the shaft, and
consequently the snare, relative to the sheath. According to several
embodiments of the invention, the system for moving the shaft relative to
the sheath includes a first (physician's) handle capable of controlling
the position of the snare, and a second (assistant's) handle proximal the
first handle and adapted to control contraction of the snare and
cauterization. The handles are coupled by a tubular sheath extension.
The physician's handle is preferably positioned along the sheath of the
snare instrument so that it is a few inches proximal to the entry port of
the endoscope handle when the distal end of the sheath is adjacent to the
distal end of an endoscope. The physician's handle serves as a grippable
element on the sheath and contains a rotating means for rotating the
shaft, so that when the physician grips that handle the physician is
capable of steering (rotating) the snare by operating the rotating means.
In addition, the physician is also capable of positioning the entire
sheath relative to the endoscope by sliding the sheath into and out of the
working channel of the endoscope. The proximal handle is operable by an
assistant and permits longitudinal movement of the shaft and snare and the
application of a cautery current to the shaft and snare.
According to other embodiments, the snare instrument is provided with a
connector which enables the snare instrument to be fixed relative to an
endoscope handle. Additionally, an embodiment is also provided in which a
single handle provides a physician with means for advancing and retracting
the sheath of the snare instrument relative to the distal end of the
endoscope, means for advancing (opening) and retracting (closing) the
snare relative to the distal end of the sheath, and means for steering
(rotating) the snare to position the snare over a polyp. Since the
physician has direct and immediate control of the entire instrument, the
snare instrument obviates the need for an assistant during the procedure,
and improves the speed and efficiency of the polypectomy procedure.
Additional objects and advantages of the invention will become apparent to
those skilled in the art upon reference to the detailed description taken
in conjunction with the provided figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is broken side elevation in section of a first embodiment of a snare
instrument according to the invention;
FIG. 2 is an enlarged cross-section taken through line 2--2 in FIG. 1;
FIG. 3 is an enlarged cross-section taken through line 3--3 in FIG. 1;
FIG. 4 is an enlarged cross-section taken through line 4--4 in FIG. 1;
FIG. 5 is a broken section view of a physician's handle assembly according
to a second embodiment of the snare instrument of the invention;
FIG. 6 is an enlarged cross-section through line 6--6 in FIG. 5, showing
the engagement of a key in a knob shaft;
FIG. 7 is an enlarged cross-section through line 7--7 in FIG. 5, at a
location proximal of the key;
FIG. 8 is a broken section view of a third embodiment of the snare
instrument according to the invention;
FIG. 9 is an enlargement of the area between lines 9a--9a and 9b--9b in
FIG. 8;
FIG. 10 is a broken section view of a fourth embodiment of the snare
instrument of the invention; and
FIG. 11 is a broken section view of a fifth embodiment of the snare
instrument of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to FIG. 1, a first embodiment of a surgical snare instrument 10
according to the invention is shown. The snare instrument 10 includes an
elongate flexible tubular sheath 12 having-a proximal end 14 and a distal
end 16, a flexible shaft 18 having a proximal end 20 and a distal end 22
extending through and axially movable relative to the sheath 12, a snare
24 coupled to or formed at the distal end 22 of the shaft 18, preferably
adjacent the distal end 16 of the sheath 12, and first and second handle
assemblies 26, 28, respectively, for moving the shaft 18 relative to the
sheath 12.
The shaft 18 is preferably a high strength, straightened (camber-free)
stainless steel wire of high elastic limit. The shaft 18 is adapted to be
bent through a tortuous path without permanent deformation. In addition,
since the shaft 18 is free of camber, it is possible to precisely rotate
the snare 24 by rotating the shaft at any point along its length.
Referring now to FIGS. 1 through 3, the physician's handle assembly 26,
which is the more distal of the two handles, generally includes a body 30
and a knob 32 mounted in the body 30 on bearings 33a, 33b in a manner
which permits the knob 32 to rotate coaxially relative to the body. The
body 30 includes a central bore 34 with one or more apertures 35, a
threaded distal end 36, and a threaded proximal end 38. The sheath 12 of
the snare instrument 10 is connected to the threaded distal end 36 of the
body 32, e.g., by means of a flare-nut connection 42. Preferably, a
stiffening sleeve 44 is provided over the sheath 12 at the connection 42.
The knob 32 includes a non-circular bore 40, e.g., having the
cross-sectional shape of a square. The knob 32 (for reasons discussed
below) is preferably at least as long as the distance of movement required
to open and close the snare 24; i.e., the length of the snare when
compressed in the sheath 12. The apertures 35 provide access to the knob
32, so that the knob 32 can be rotated relative to the body 30, e.g., by a
physician.
A portion of the shaft 18 extending through the bore 40 of the knob 32 is
provided with a key 46; that is, a spline element fixed on and about the
shaft 18 or, alternatively, rigidly and fixedly interposed between two
portions of the shaft. The key 46 preferably has a rectangular shape but
may have another non-circular shape. The key 46 is slidably axially
movable within the bore 40. Therefore, the shaft 12 may be moved axially
through the bore 40 (and that is why the length of the knob 32 is
preferably at least as long as the distance of movement required to open
and close the snare). However, when the knob 32 is rotated relative to the
body 30, the key 46 within the bore 40 is rotated and, consequently, the
shaft 18 and snare 24 are rotated relative to the sheath 12.
The distal handle assembly 28 is preferably positioned approximately 210 cm
from the distal end 16 of the sheath 12 for a snare instrument 10 designed
to be inserted into a 200 cm endoscape. Thus, the physician can grip the
body 30 in a manner which permits rotating the knob 32 relative to the
body, and hence the snare 24 relative to the sheath 12, while using the
body 30 as a grip to axially position the snare instrument 10 within the
working channel of an endoscope.
The shaft 18 extends out of the proximal end 38 of the body 30 to the
proximal handle assembly 28, or assistant handle. The proximal handle
assembly 28 preferably includes a stationary member 50 and a spool member
52 slidable relative to the stationary member. The stationary member 50
includes a longitudinal throughbore 56 through which the proximal end 20
of the shaft 18 extends, a transverse slot 58, a proximal thumb ring 60,
and a distal threaded connector 62. The proximal end of the shaft 18 is
preferably provided with a conductive stiffening sleeve 64, and a
cylindrical conductive bearing 66 is coupled about the proximal end of the
stiffening sleeve 64. The spool member 62 includes a cross bar 68 which
extends through the transverse slot 58 to secure the spool member 52 on
the stationary member 50. In addition, the spool member 62 preferably
includes a cautery plug 70. The conductive bearing 66 extends through the
cross bar 68 and a collar 74 secures the bearing 66 in the cross bar 68 in
a manner which permits the conductive bearing to freely rotate within the
cross bar 68. A spring 72 extends between the cautery plug 70 and the
conductive bearing 66, and provides a contact between the plug 70 and the
bearing 66 regardless of the rotational position of the bearing 66.
Movement of the spool member 52 relative to the stationary member 50
causes the snare 24 to extend from and retract into the distal end 16 of
the sheath 12.
Referring to FIGS. 1 and 4, an electrically insulative extension sheath 80
extends over the shaft 18 between the proximal end 38 of the body 30 and
the distal end 62 of the stationary member 50, coupled, e.g., via
flare-nut connections 82, 84. Thus, there is a continuous outer connection
joining, yet spacing apart, the distal handle assembly 26 and the proximal
handle assembly 28. A stiffening sleeve 86 is preferably provided over the
extension sheath 80 at the proximal end 38 of the body 30, and another
stiffening sleeve 88 is preferably provided over the extension sheath 80
at the distal end 62 of the stationary member 50.
In use, the physician introduces the snare instrument 10 into the endoscope
(not shown), typically by means of a port in the endoscope handle which
communicates with the working channel of the endoscope. Then, the
physician gives the proximal assistant's handle 28 to the assistant. The
physician then grips the body 30 of the distal physician's handle 26 of
the snare instrument and uses it to position the distal end 16 of the
sheath 12 adjacent to the polyp to be excised. The physician then
instructs the assistant to extend the snare, which is performed by moving
the spool-member 52 relative to the stationary member 50. The physician
then uses the distal handle 26 to simultaneously axially position and
rotate the snare over the polyp. Then, the physician instructs the
assistant to close the snare and sever the polyp, using cautery if
desired. In this manner, the physician controls the means of positioning
the snare onto the polyp, and the assistant controls the opening and
closing of the snare and the cauterization.
In the first embodiment, as discussed above, it will be appreciated that
the knob 32 is preferably at least as long as the distance of movement
needed to open and close the snare 24. However, turning now to FIGS. 5-7,
according to a second embodiment of a snare instrument 110, the key 146 on
the shaft 118 is made sufficiently small in diameter such that it can pass
partly into the bearings 190, 191 on the body 130 (which support the knob
132) and proximal and distal ends 136, 138 of the body 130, or even into
the sheath 112 and extension sheath 180, and their respective stiffening
sleeves. Accordingly, the knob 132 is provided with a hollow knob shaft
192 having a non-circular bore 140 which rotatably engages the key 146 on
the instrument shaft 118. The knob shaft 192 extends beyond the proximal
and distal ends of the knob 132. The knob shaft 192 extends into bearings
190, 191 of the body 130 which allows the knob 132 and knob shaft 192 to
spin within the body 130. The knob shaft 192 may optionally extend through
the proximal and distal ends 136, 138 of the body 130, into the sheath (on
the distal end) and into the extension sheath (on the proximal end). In
this manner, it is possible to achieve a large range of axial motion
(e.g., 3.5 inches) while having a knob 132 of much shorter dimension
(e.g., 1.25 inches). It should be noted that if the key 146 has a
substantial length (e.g., 0.75 inch), the body 130 and knob 132 can be
made even shorter, since it is necessary for only a portion of the key 146
to be engaged with the non-circular bore 140 of the knob shaft 192 at any
time.
In addition, while the first embodiment describes a shaft 18 that is
monolithic and continuous from the snare 24 to the proximal handle
assembly 28, the shaft may alternatively be a composite structure.
Specifically, referring to FIGS. 8 and 9, according to a third embodiment
of the invention, the straightened, torsionally-stiff, camber-free section
of the shaft 218 need only extend from the snare to the knob 232. A swivel
joint 290 may be interposed on the shaft 218 between the knob 232 and the
proximal handle assembly, and join the shaft 218 to a flexible or stiff
proximal shaft extension 292 which extends to the proximal handle
assembly. The proximal end 294 of the shaft 218 is preferably formed into
an enlarged section, i.e., a head 296, or a separate, enlarged head may be
attached to the proximal end of the shaft. A swivel tube 298, preferably
made of a malleable alloy, such as brass or stainless steel, is provided
over the head 296. A distal end 299 of the swivel tube 298 is swaged or
crimped to form a loose fit on the shaft 218, while being small enough to
retain the head 296. The swivel tube 298 is placed onto the shaft 218 such
that the head 296 is trapped inside the non-crimped portion 300 of the
swivel tube 298. The extension shaft 292 is pushed into the proximal open
end 304 of the swivel tube 298, and the swivel tube 298 is firmly crimped
onto the extension shaft 292. The extension shaft 292 is preferably made
of either a flexible cable, for example, a 1.times.7 stranded stainless
steel cable preferably of 0.032 inch diameter, or a solid wire of a
springy material such as stainless steel, for example, a 0.020 inch
diameter 304 stainless steel spring-temper wire. The extension shaft 292
extends proximally from the swivel tube 298 to the spool so that it
transmits reciprocating longitudinal motion of the spool through the
swivel tube 298 to the shaft 218.
This variation in construction of the extension shaft 292 is allowed
because the purpose of the extension of the shaft 218 is merely to
transmit the reciprocating axial motion imparted by the proximal handle;
thus, if there exists a freely rotational joint between distal shaft 218
and the extension shaft 292, there is no requirement for the extension
shaft to be straight, torsionally-stiff, or camber-free.
Turning now to FIG. 10, according to a fourth embodiment of the invention,
the distal handle assembly 326 includes a mount 350 capable of firmly
coupling the distal handle assembly 326 to a port in an endoscope handle
(not shown), for example, by interference fit. In a preferred
configuration, the mount 350 includes a coupling-fitting 352 which is
couplable to the port of the endoscope, and a connector 354 which is
slidably movable, yet capable of being secured in a position, relative to
the coupling fitting 352. The connector 354 has a proximal end 356 which
is threadably coupled to the distal end 336 of the body 330.
The coupling fitting 352 includes a cylindrical block 358 having an axial
bore 360, and a tubular nosepiece 362 secured in the axial bore 360. The
connector 354 includes a stepped bore 364 having a relatively large
central portion 366, and relatively smaller proximal and distal portions
368, 370. The central portion 366 of the stepped bore 364 is sized to
permit relative axial movement over the block 358. The distal portion 370
of stepped bore 364 is sufficiently large to permit axial movement of the
connector 354 over the nosepiece 362. A locking screw 372 extends radially
into the central portion 366 of the stepped bore 364 of the connector 354
such that the screw 372 may be rotated to tighten against the block 358 to
lock the connector 354 axially relative to the block. The proximal end 314
of the sheath 312 extends through the nosepiece 362 and block 358 and is
fixedly couple in the proximal portion 368 of the stepped bore 364. Other
aspects of the fourth embodiment are substantially as described above with
respect to the first embodiment.
In use, the snare instrument is inserted through a port of an endoscope
until the nosepiece 362 of the snare instrument is stably inserted in the
port. The distal end of the sheath of the snare instrument may then be
adjustably fixed relative the distal end of the endoscope by adjusting the
connector 354 (and hence the handle 326, shaft 318, and sheath 312) over
the block 358. When the sheath is correctly positioned, screw 372 may be
set. The distal handle 326 may then be operated, as described with respect
to the first embodiment, to rotate the shaft 318 and snare relative to the
sheath 312. Likewise, a proximal handle assembly, as described with
respect to the first embodiment, may then be manipulated to longitudinally
move the shaft 318 to open and close the snare (the sheath having been
previously set in position). With the above described embodiment, it may
be possible for the physician to operate without an assistant as the axial
placement of the snare instrument is established and set prior to rotation
and activation of the snare loop.
Referring now to FIG. 11, according to a fifth embodiment of the invention,
a single handle assembly 427 capable of being fixed relative to an
endoscope handle is provided. The handle assembly 427 of the snare
instrument includes all of the controls previously provided in the
proximal and distal handle assemblies, and is substantially similar to the
distal handle assembly 326, described above, with the additional
incorporation of the snare opening and closing functions. To that effect,
a sliding spool assembly 428 for longitudinally moving the shaft 418
relative to the sheath 412 may be substantially rigidly fixed to the
proximal end 438 of the body 430. For example, a distal end 462 of a
stationary member 450 of the spool assembly 428 may be threadably mated
with the proximal end 438 of the body 430. The spool assembly is
preferably otherwise substantially as described with respect to proximal
handle assembly 28 of the first embodiment of the invention.
The resulting device is fixedly couplable relative to an endoscopic handle
and provides to the physician the following controls: a means for
controllably advancing, retracting, and setting the sheath of the snare
instrument relative to the distal end of the endoscope; a means for
advancing (opening) and retracting (closing) the snare relative to the
distal end of the sheath; and a means for steering (rotating) the snare to
position the snare over a polyp. Since the physician has direct and
immediate control of the entire instrument, the snare instrument obviates
the need for an assistant during the procedure, and improves the speed and
efficiency of the procedure.
There have been described and illustrated herein several embodiments of a
surgical snare instrument. While particular embodiments of the invention
have been described, it is not intended that the invention be limited
thereto, as it is intended that the invention be as broad in scope as the
art will allow and that the specification be read likewise. Thus, while
the use of a particular monolithic and composite shafts have been
disclosed with respect to a snare instrument, it will be appreciated that
other flexible shafts may also be provided. Also, while the cautery
connector has been shown on the proximal handle, it will be appreciated
that the cautery connection may be provided in the physician's handle, or
elsewhere along the length of the device, provided that the cautery
connection will not interfere with the axial longitudinal and rotating
motions of the shaft. Furthermore, while particular shapes and
configurations have been described with respect to the proximal and distal
handles, it will be appreciated that other shapes and configurations may
be provided therefor. As such, it will also be appreciated that other
configurations which provide a gripping handle for the sheath, means for
rotating the shaft, and means for longitudinally moving the shaft may be
used. For example, a control knob which rotates about an axis
perpendicular to the axis of the shaft via a right-angle drive (using two
meshing bevel gears) may be used to rotate-the shaft. The gears may be
configured to permit step-up or step-down rotation, for example, such that
rotation of the shaft rotates the shaft twice as much or one-half as much.
In addition, levers, gears, friction wheels, pulleys, links, etc., may be
used to longitudinally move the shaft within the sheath, and the snare
relative to the distal end of the sheath. Moreover, while a particular
nosepiece has been described for use in the fourth and fifth embodiment,
it will be appreciated that other nosepieces enabling stable coupling of
the snare handle to an endoscope handle may be used. For example, a
threaded connector capable of threading into or over a port on the
endoscope handle may be used. Also, in the fourth and fifth embodiment,
the mount and the body may be integrally formed or molded, and in the
fifth embodiment, the body and the proximal sliding spool assembly may be
integrally formed or molded. In addition, it will be appreciated that
aspects of the various embodiments may be combined. For example, but not
by way of limitation, the key of the second embodiment or the swivel joint
of the third embodiment may be used in either of the fourth and fifth
embodiments. Furthermore, the described handle assemblies may be used with
other surgical instruments where both axial and rotational movement of a
control member relative to a tubular member is required. For example, the
handle may be used in laparoscopic and endoscopic instruments, generally,
which include an end effector other than a snare loop. For example, and
not by way of limitation, end effectors such as baskets and forceps may be
used with the handle. It will therefore be appreciated by those skilled in
the art that yet other modifications could be made to the provided
invention without deviating from its spirit and scope as claimed.
Top